Spring's the time for lucerne

Published 26 March 15

If you are considering growing lucerne this year, spring is the right time for successful establishment. That’s the key message from a recent DairyCo-funded trial* investigating how we can grow lucerne in Great Britain. Researchers at Harper Adams University(HAU), SRUC and the University of Reading have been investigating the effects of timing and cover crops on the success of lucerne establishment.

Spring versus autumn establishment

Over the last three years, there was repeated failure of the late summer/autumn planted lucerne in the study at the three different sites: Dumfries, Shropshire and Reading.

“Lucerne requires higher soil temperatures to grow than grass and because it is very slow to establish and there is often insufficient time in autumn to get a crop growing before soil temperatures drop and growing conditions deteriorate,” explains HAU researcher Louisa Dines. “It is also less competitive than weeds at this time of year.”

In contrast, spring establishment was more reliable, with successful establishment achieved at all three sites in most years.

Cover crop

Weed burden is a significant problem at establishment, even in spring crops, with as much as 70% of yield at first cut being made up by weeds, in some of the trial plots.

Image 1: Lucerne can suffer from significant weed burden at first cut.

A cover crop of spring barley, sown at half rate, was trialled to find out whether this could help reduce the weed burden, and if this would have any effect on the long-term crop of lucerne.

Overall, there was no clear effect of cover crop on first cut dry matter yields. Across the three year trial, some sites showed greater yields with a cover crop and some showed greater yields without one. The use of a cover crop, however, did appear to reduce the amount of weeds at first cut (by almost 40% on some sites). Regardless of this, sowing with a cover crop did not result in any long-term benefit – yields of lucerne at second cut were similar between the cover crop and no cover crop treatments.

“Our results show how important achieving a clean seed bed is for Lucerne, as it can be heavily hit by weeds at establishment,” comments Louisa Dines. “However, once the initial weed burden has been removed at first cut, the burden should be greatly reduced.”